[sdiy] Polyphonic keyboard scanner

[David G. Dixon]

Thanks to all for the replies.  I am very interested in looking at the
Oberheim OB-Xa schematic.  Any hints where I might find it?

Also, I bit the bullet and bought a book on microcontrollers today (at the
brilliant Powell's Technical Bookstore in downtown Portland, OR -- if you've
never been, and you find yourself in the area, you really must check it
out!).  The book is "Programming and Customizing PICmicro Microcontrollers"
by Myke Predko.  It's nearly 1200 pages, and it came with a PCB in an
envelope behind the front cover for building a PIC programmer (how cool is
that?!? -- I've never bought a book with a PCB in it before!).  Get this: it
was only $22!  And, the project on page 922 is a switch matrix key
interface!

> I cloned and upgraded the Tim Orr ETI Polysynth's polyphonic controller.
> 
>  > http://rubidium.dyndns.org/cag/pdf/etipoly.pdf
> 
> There are some mistakes in the poly assigner schematic. I have all the
> errors noted down somewhere - as well as a detailed section by section
> break down of what is actually going on. I may try and dig it out if I
> can find it.
> 
> Other things to note: Cyclic assignment, like the OB-Xa, with optional
> note stealing and switchable total voice number, 1, 2, 4 or 8. Unusual
> +/-5V buss bar on the keyboard. Linear glide with OTA control.